Rare Earth Magnet & Motor Materials worked example

Sintering Shrinkage at 9.2% shrinkage-related scrap rate: a worked example

Push shrinkage-related scrap rate up to 9.2% and the picture changes. This example computes every intermediate figure at that operating point. Use it to budget yield loss from dimensional shrink when sintering NdFeB or SmCo magnet blanks.

The inputs for this scenario

  • Green compacts sintered: 8,000 parts (unchanged)
  • Rare earth material value lost per scrapped compact: 6.5 $/part (unchanged)
  • Shrinkage-related scrap rate: 9.2 % (raised for this scenario; the documented default is 8)
  • Furnace run and atmosphere overhead: 5,000 $ (unchanged)

Working through the calculation

  • Applying the documented formula (Total shrinkage loss = compacts sintered x material value lost per part x shrinkage scrap rate% + furnace overhead) to the inputs above produces each figure below.
  • At this operating point the engine returns 9,784 $ for total sintering shrinkage cost, the number this scenario is built around.
  • At this operating point the engine returns 1.22 $ / piece for sintering shrinkage cost per unit.
  • At this operating point the engine returns 4,784 $ for variable sintering shrinkage cost.
  • At this operating point the engine returns 5,000 $ for fixed sintering shrinkage adder.

How this compares with the baseline

  • Against the tool's baseline example, where shrinkage-related scrap rate sits at 8% and the headline result is 9,160 $, this scenario comes in 6.81% above the baseline at 9,784 $.
  • It sums the material value lost to shrinkage scrap plus fixed furnace overhead, then divides by compacts to give a cost per piece. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • Total sintering shrinkage cost: 9,784 $ (headline result)
  • Sintering shrinkage cost per unit: 1.22 $ / piece
  • Variable sintering shrinkage cost: 4,784 $
  • Fixed sintering shrinkage adder: 5,000 $

Run it with your numbers

  • Every input above is editable in the live Sintering Shrinkage calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.